1. Pesticide Residues in Estonian Arable Soils
Kadri Allik
Priit Penu
Estonian Agricultural Research Centre
Soil Monitoring Bureau
11th Nordic Pesticide Residue Workshop
June, 2015

2. Pesticide influence on soil
Pesticide influences on soil depend on its composition and appearing time varieties.
Significant negative impact of pesticides on soil biota has not been proved.
Herbicides inhibit nitrogen producing bacteria.
Fungicides and insecticides have influence on soil fauna.
Insecticides affect N-cycle.
Pesticides imapct on bacterial communites by reducing or changing their activity and composition.
Pesticides cause decline in soil biodiversity.
Source: European Soils

3. Guadeloupe and Martinique islands
High quantity of chlordecone was used in banana cultivation.
Soil contamination occured.
Pesticides were carried to sea.
Fishing was banned in costal
ares. Social disaster emerged.

4. Limits for hazardous agents in soil
Target, mg/kg
Limit in residential areas, mg/kg
Limit in industrial areas, mg/kg
2,4-D
0,05
0,5 2
DDT
0,1 5
Synthetic pesticides
(total of active ingredient) 20
Data source: Regulation No 38 of the Minister of Environment,

5. Stockholm Convention on Persistent Organic Pollutants
The convention covers following pesticides used in Estonia: toxaphene, hexachlorobenzene, polychlorinated biphenyls (PCB-s), hexachlorocyclohexanes, lindane, hexabromodiphenylether, pentabromodiphenylether, DDT.
Hexachlorocyclohexanes banned in 1967 and chloro-organic pesticides import was banned in 1968.
Estonian action plan of the Stockholm convention do not consider pesticide residues in soils as priority.
Agent
Duration of usage
Total amount used, tonnes
Reserves of agent
Toxaphene
10,65
Unknown
Hexachlorobenzene (HCB)
3,99
DDT
191,3

6. Determination of pesticide residues at present
Agricultural Research Centre (ARC) laboratory is able to determine 300 active ingredients from soil using different chromatographic methods.
In Soil Monitoring Bureau there are pesticides residues analysed in case of three studies or monitoring.
The aim of collaboration between Ministry of the Environment, Agricultural Board and Agricultural Research Centre is to find additional ways to examine actually used active ingredients.

7. Studies in ARC including pesticide analysis
Study about Minimum Soil Tillage
(Soil Tillage Study)
Study about Dynamics of Soil Nutrients in Nitrate Vulnerable Zone
(NTA Study)
Soil Monitoring Study as Part of National Environmental Monitoring Programme
(Soil Monitoring Study)
Gross Nutrient Balances and Pesticide Use Study
Figure 1. Nitrate Vulnerable Zone in Estonia.

8. Results of different studies 2005-2014

9. Clean samples vs samples consist pesticides residues 2005-2014

10. The distribution of most common active ingredients

11. The comparison of pesticides in mulch and in soil (Soil Tillage Study)

12. Share of different pesticide residues in 2007-2014 (NTA Study)

13. Results of NTA Study

14. Active ingredients compared in NTA areas and other areas in 2014

15. Organic farming and pesticide residues
In 2014 pesticide residues were found from a organic farming field.
Buffer zones around the conventional tillage fields and organic farming fields are needed.
Monitoring of arable lands under organic farming fields.
Agricultural Board found pesticides (2,4-D, glyphosate) from products of organic farming in Control of pesticide residues needed in organic fields?

16. Organic farming and conventional tillage
331 land parcels found where arable lands under conventional tillage and under organic farming are next to each other.
Figure 2. Organic farming field (green) between fields under conventional tillage.

17. Some observations
Trifluralin (herbicide) remains in soil at least 4-5 years.
MCPA (herbicide) remains in mulch longer than in soil.
Fungicides remain in soil at least 6-7 months.
Generally the content of pesticide residues is much lower than their target number.
Some residues containing in soil are below its measurement error.
In 2014 the first time was found total amount of pesticide residues (1,21 mg/kg) that overcome the target number (0,5 mg/kg).

18. Monitoring issues
Method of sample collection time, depth of taking samples.
Content of pesticides in the lower layers leaching.
Applicable active ingredients vs capability of laboratory.
Samples are collected after crop harvest in September and sometimes winter crop have already sowed.
Even glyphosate residues were found, the concentration of AMPA was not detected. Determination problem?
Decomposition product (DDE) of the DDT was found even at present, but it is below the determination limit (<0,01 mg/kg).

19. Thank you for the listening!
© Arne Ader